Observing the sun using a telescope is fraught with difficulty. Direct vision can risk eye damage. Solar filters are often added to astronomical telescopes. These can fall off or crack due to the sun's heat, exposing the viewer's eye to the concentrated rays of the sun. In addition, astronomical telescopes are often large, unwieldy, hard to point and optimized for viewing dim objects at night. It is desirable to have a small, easy to use telescope that is as safe as possible. A telescope that can project a solar image onto a viewing surface allows users to observe sunspots and sketch drawings of the projected solar image onto a removable writing surface placed on the viewing surface.
A device is described in U.S. Pat. No. 4,437,736 wherein the sun viewing apparatus is a self-contained device consisting of a light shield with an aperture for admitting the rays of the sun and a series of pre-aligned lenses and prisms to display an image of the sun on a screen to reduce the threat of eye damage. This device suffers from difficulty in aligning the telescope with the sun and maintaining instrument alignment as the sun moves across the sky. In general, the sun moves through its own diameter across the sky in about two minutes, so frequent readjustment of the device is necessary to maintain a projected solar image. Adjusting the telescope alignment should be simple and easy to accomplish. However, this device does not provide simple means or methods for adjusting the telescope to the proper orientation for solar observation. Generally props must be placed beneath a corner of the instrument to tilt the telescope to the proper position in order to project an image of the sun.
Mounting systems for supporting a telescope are disclosed in U.S. Pat. Des. 247,854 wherein a portion of the telescope is in the form of a sphere that rests on a curved mount such that friction between the curved mount and the spherical telescope maintains the telescope orientation. The cylindrical portion of the telescope, which extends from the sphere, shifts the balance point of the telescope such that a significant amount of force is required to overcome the stabilizing friction to adjust the alignment of the telescope.
Another telescope and telescope support device is disclosed in U.S. Pat. No. 4,470,672 that describes a telescope with a large external ring attached to the side and end of a telescope, which acts as a mounting system for attachment of the telescope to a support. With the center of gravity adjusted to be close to the middle of the ring, the telescope is supposed to remain at a specified position at any azimuth or elevation. However, because the telescope center of mass is not located at the origin of the support ring additional mechanical devices are necessary to stabilize the telescope at certain elevations. The elevation of the telescope is maintained by friction. However, since the location of the telescope center of mass is variable depending on telescope elevation, the amount of stabilizing force e.g. friction necessary to maintain a specified elevation varies. Spring-loaded adjusters or other mechanical devices are disclosed to provide variable amounts of friction between the mounting ring and the telescope support device, sufficient to stabilize the telescope orientation. This system is complex; involving a large number of pieces and several adjustment points that increase the cost of the telescope, telescope size and the level of difficulty in using the telescope.
There is a need for a solar telescope that can be quickly and easily aligned with the sun such that an image of the sun is readily projected to a viewing screen. In addition, the telescope should have a support system that facilitates alignment and provides sufficient stability regardless of azimuth or elevation of the telescope.